Frequency conversion with positive nonlinear resistors
Chester H. Page · Journal of research of the National Bureau of Standards · 1956
A nonlinear r esistor s ubject to an almost periodic voltage will absorb power at some frequ encies, a nd supply power at other frequencies.Necessary a nd s ufficien t relations a mon g these power s are found.Among the practical conseq uences are t he resul ts: (1) modulation effici ency cannot exceed unity, (2) subharmonics are not produced , and (3) the effici cncy of generating an nth harmonic cannot exceed 1/n2 .